When thousands of public-health workers fan out across Pakistan today in the first day of a three-day campaign to vaccinate the country’s children against polio, an estimated 250,000 won’t be receiving the potentially lifesaving dose, the social-affairs secretary for Pakistan’s Federally Administered Tribal Areas, Aftab Akbar Durrani, told VOA’s Urdu Service yesterday. Last month, militant leaders in two of the most lawless districts of Pakistan’s Federally Administered Tribal Areas (FATA) declared that the vaccination teams would not be allowed to conduct their campaign, declaring that the locally run program was merely a ruse to allow American spies to penetrate the region. “In the garb of these vaccination campaigns, the U.S. and its allies are running their spying networks in FATA, which has brought death and destruction on them in the form of drone strikes,” wrote Mullah Nazir, one of South Waziristan’s major militant commanders, in a pamphlet that was widely distributed on June 25. His screed echoed that of a commander in North Waziristan, Hafiz Gul Bahadur, whose own pamphlet from a week earlier was even more direct: “We don’t want benefits from well-wishers who spend billions to save children from polio, which can affect one or two out of hundreds of thousands, while on the other hand the same well-wisher (America) with the help of its slave (Pakistan’s government) kills hundreds of innocent tribesmen including old women and children by unleashing numerous drone attacks.” The ban on vaccinations, he continued, would not be lifted until the drone strikes stop.

Both Nazir and Bahadur reiterated to TIME through a special correspondent in Peshawar yesterday that they would not reconsider the ban on vaccination teams, citing the ongoing drone campaign in the country’s tribal regions.

As my colleague Jeffrey Kluger wrote in the wake of the first pamphlet,

Using children as medical poker chips is indefensible under any circumstances, but the Pakistanis do have other reasons to be suspicious of Westerners bearing vaccines. In the months leading up to [Osama] bin Laden’s killing in May 2011, a local doctor who was also working for the CIA ran a hepatitis-vaccination campaign in and around Abbottabad, where bin Laden was holed up. The real purpose was to try to obtain DNA samples that would confirm bin Laden or his family members were indeed in residence. That, surely, figured in the Taliban’s decision.

But the militant’s math — “one or two out of hundreds of thousands” — demonstrates an egregious misunderstanding of the sinister swath that polio can cut through a population of healthy, active kids, according to Kluger:

For every clinical case of polio, there are 200 subclinical ones that can present themselves merely as a bad summer cold; but that’s 200 active carriers who can and do spread the wild virus. Even people who are infected with what will turn out to be a crippling strain of the disease do not know they’re sick for a week or more, as the virus makes the long journey from the throat to the gut to the bloodstream — multiplying explosively all the way — and finally to the anterior horns of the spinal cord and the medulla oblongata of the brain, where it wipes out the cells that signal the muscles, paralyzing them forever.

The vaccination campaigns take place every six weeks or so; each child under the age of 5 requires three doses to ensure that he or she is truly immune. So not only will the militants’ ban leave the very young vulnerable, it will also negate the effects of previous vaccination campaigns. That too will have long-term consequences, not just for the children but for the worldwide campaign to eradicate polio for good, according to Kluger:

Until very recently, polio appeared to be at the very brink of eradication — which would make it only the second disease ever to be wiped out in the wild, following smallpox, which was finally vaccinated out of existence in 1977. As recently as 1988, there were 350,000 cases of polio worldwide, distributed across 125 countries. Thanks to an aggressive, 24-year eradication campaign headed by UNICEF, WHO, the CDC and Rotary International, however, there were only 650 cases worldwide last year and only 73 so far this year — confined to just three countries: Afghanistan, Pakistan and Nigeria.

Afghanistan’s 10 cases this year have occurred in the country’s south, along the border with Pakistan, where ongoing fighting has prevented vaccination teams from accessing the children. Pakistan’s 22 cases, however, have occurred in all four of the country’s provinces, a worrying sign of the disease’s spread. Nigeria, with 52 cases of paralysis this year, will still be the most difficult country to tackle, though numbers have plummeted over the past four years. (There have been 11 new cases in Nigeria in the three weeks since Kluger wrote his story, which explains the discrepancy.)

Still, with so few cases worldwide, the prospect of global eradication is tantalizingly close. The longer the Pakistani militants’ ban on vaccination goes on, the more difficult it will be to reach that goal. They might think they are making a point, instead they are holding the lives of Pakistan’s, and the world’s, children hostage. When challenged on that point, both Nazir and Bahadur argued that they were looking out for the long-term good of their people. It’s hard to see how.

Aryn Baker is the Middle East Bureau Chief for TIME, covering politics, society, culture, religion, the arts and the military in the greater Middle East, including Pakistan and Afghanistan. She currently resides in Beirut, Lebanon.